I suspect the fuzzy glossary matches from getting a too high priority. The lower glossary contains the plural 'Schrauben' and has a LOW priority. In the upper glossary (priority MEDIUM) the singular 'Schraube' is contained. It looks like this one is being used for AA, whereas the full form 'Schrauben' should have been selected:
Besides that: a different colour for fuzzy glossary matches (dark orange?) would be very useful.
I just got another segment with the same word 'Schrauben'. Same matches listed. This time 'bouten' is AA'd correctly, because I've overruled 'Schroef' in the segment shown above, by 'Bouten' (via the context menu).
So the good news is that the overruling part works as advertised.